Areciboradar observations on 5–6 March 2012 showed that 1999 RD32 is approximately 5 kilometers (3 mi) in diameter[5] and has an estimated albedo of only 0.04.[5] Other sources calculate a smaller diameter of 1.63 kilometers based on a dated assumption, that the object is a stony rather than a carbonaceous asteroid.[4] The two visible lobes suggest that 1999 RD32 is a tight binary asteroid or contact binary.[5] About 10–15% of near-Earth asteroids larger than 200 meters are expected to be contact binary asteroids with two lobes in mutual contact.[12]

(A) List includes near-Earth approaches of less than 5 lunar distances (LD) of objects with H brighter than 18.(B)Nominal geocentric distance from the Earth's center to the object's center (earth radius≈6400 km).(C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y.(D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD)(E) Color codes: unobserved at close approach observed during close approach upcoming approaches